Add a simple compositor for Sky

sky/compositor/surface_holder.h

Index: sky/compositor/surface_holder.h
diff --git a/sky/compositor/surface_holder.h b/sky/compositor/surface_holder.h
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+++ b/sky/compositor/surface_holder.h
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+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SKY_COMPOSITOR_SURFACE_HOLDER_H_
+#define SKY_COMPOSITOR_SURFACE_HOLDER_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "mojo/services/public/interfaces/surfaces/surface_id.mojom.h"
+#include "mojo/services/public/interfaces/surfaces/surfaces.mojom.h"
+#include "mojo/services/public/interfaces/surfaces/surfaces_service.mojom.h"
+#include "ui/gfx/geometry/rect.h"
+
+namespace mojo {
+class Shell;
+}
+
+namespace sky {
+class SurfaceAllocator;
+
+class SurfaceHolder : public mojo::SurfaceClient {
+ public:
+  class Client {
+   public:
+    virtual void OnReadyForNextFrame() = 0;
+    virtual void OnSurfaceIdAvailable(mojo::SurfaceIdPtr surface_id) = 0;
+    virtual void ReturnResources(
+        mojo::Array<mojo::ReturnedResourcePtr> resources) = 0;
+
+   protected:
+    virtual ~Client();
+  };
+
+  explicit SurfaceHolder(Client* client, mojo::Shell* shell);
+  ~SurfaceHolder() override;
+
+  void SetSize(const gfx::Size& size);
+  void SubmitFrame(mojo::FramePtr frame);
+
+ private:
+  // mojo::SurfaceClient
+  void ReturnResources(
+      mojo::Array<mojo::ReturnedResourcePtr> resources) override;
+
+  void OnSurfaceConnectionCreated(mojo::SurfacePtr surface,
+                                  uint32_t id_namespace);
+
+  Client* client_;
+  gfx::Size size_;
+  scoped_ptr<SurfaceAllocator> surface_allocator_;
+  mojo::SurfacesServicePtr surfaces_service_;
+  mojo::SurfacePtr surface_;
+  mojo::SurfaceIdPtr surface_id_;
+
+  base::WeakPtrFactory<SurfaceHolder> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(SurfaceHolder);
+};
+
+}  // namespace sky
+
+#endif  // SKY_COMPOSITOR_SURFACE_HOLDER_H_